Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon, forming an integrated circuit.
Fuses are devices that are used in semiconductor devices for many applications, such as in array redundancy, electronic chip identification (EID), recording data such as performance or test parameters, and array repair, as examples. Laser fuses (l-fuses) are fuses that are programmed with a laser. The laser uses a high temperature to cause a break in a conductive material of the l-fuses, blowing the l-fuses. However, l-fuses require a relatively large amount of surface area on a semiconductor device to avoid causing damage to surrounding portions of the integrated circuit when the fuses are blown. Furthermore, a special tool is required to program or blow l-fuses, and the point in the manufacturing process flow that l-fuses may be programmed is limited to early time periods in the process flow, e.g., after wafer tests.
Electronic fuses (e-fuses) are fuses that require a smaller amount of surface area on a chip than l-fuses. E-fuses are programmed or blown by the application of a higher than usual amount of current, which causes electromigration of a portion of the e-fuse and increases the resistance. E-fuses may be blown at multiple test and application stages and have a low risk of causing damage to surrounding devices during programming.
Some e-fuse designs have reliability problems because they are required to be programmed or blown at large amounts of applied current.
What are needed in the art are improved e-fuses in semiconductor devices and methods of manufacture thereof.